1. Field of the Invention
The present invention relates to a bin for the culture of mushroom that is suitably used for cultivating mushrooms such as shiitake (Lentinus edodes (Berk.) Sing.).
2. Description of the Relevant Art
The growth stage of mushrooms in a bed cultivation generally comprises vegetative growth and reproductive growth. At the cultivation step of the vegetative growth, holes are provided for inoculation of the substrate which is filled in the bin for culture; mushroom spawn are inoculated in these holes and in a culture room; hyphae are allowed to spread into substrate in the bin for culture that are capped for preventing miscellaneous harmful fungi from entering. On the other hand, at the reproductive growth step, the substrate is taken out and only the removed mushroom culture medium is placed in the culture bin for growing in a growth room. The bin for culture are composed divided in the upper half bin and lower half bin; both can be attached and detached by a screw mechanism so that the substrate can be taken out during the growing process.
In the culture process of hyphae, enough ventilation into the bin for culture is required in order to exhaust a large volume of generated carbon dioxide while it is necessary to prevent harmful fungi from entering. Poor ventilation in the culture bin may obstruct breathing of the hyphae and their efficient propagation, thereby making the cultivation period longer and deteriorating the mushroom quality.
In view of this, conventionally, a permeable cap was fitted to the mouth provided to the culture bin to ventilate inside the bin. Among known caps for this purpose, for example, Japanese Utility Model Publication No. 27402/'91 (Hei-3) has proposed a cap for culture bin that has a zigzag air flow path in the cap body whereby the internal part of the culture bin communicates with the outside when the cap is fitted to the bin; Japanese Utility Model Provisional Publication No. 91945/'87 (Sho-62) has disclosed a cap for a culture bin that has an open part and a ventilating part in the cap body, both parts being covered with permeable material under which absorbents of carbon dioxide are accommodated.
However, these known caps have been unsatisfactory for adequate and efficient ventilation because: the ventilation is secured only through a cap located at the bin mouth of the bin for culture; the ventilation is made through permeable material provided on the cap but is not satisfactory from the viewpoint of permeability; and carbon dioxide is heavier than air. The breathing activity is highest in the cultivating step, when the substrate swells by the hyphae's spread during the whole cultivation process, and carbon dioxide tends to accumulate in the bin.